“this is probably the biggest known asteroid to have come this close.”
As spotted by SpaceWeather. At about 1700 UT (6pm BST) today Asteroid 2011MD will fly past only 12,300 kilometers (7,600 miles) above the Earth’s surface. [Image credit NASA/JPL] As the diagram shows, that’s close enough to be affected by Earth’s gravity. This small asteroid, only 5-20 meters in diameter, is in a very Earth-like orbit about the Sun, but an orbital analysis indicates there is no chance it will actually strike Earth on Monday. The incoming trajectory leg passes several thousand kilometers …